Electronic gear flowmeter based on rotary encoder and measurement method

Abstract

The application discloses an electronic gear flowmeter based on a rotary encoder, comprising a mechanical gear flowmeter, a rotary encoder, a decoder and a subdivision algorithm module, the output shaft of the mechanical gear flowmeter is connected with the code disc of the rotary encoder, and the subdivision algorithm module and the decoder are connected with the rotary encoder. Meanwhile, the application also discloses a measurement method based on the electronic gear flowmeter. The application carries out photoelectric conversion on the detection result of the mechanical gear flowmeter, and then processes the signal converted by photoelectric conversion, so that the detection accuracy is improved.

Description

Technical Field

[0001] This invention relates to the field of measurement technology, and specifically to an electronic gear flow meter based on a rotary encoder and a measurement method thereof. Background Technology

[0002] In industries such as pharmaceuticals, chemicals, brewing, and energy, a large portion of raw materials are fluids, including liquids and gases. During production, the precise and stable supply of raw materials directly impacts the reaction process and product quality. Therefore, accurate flow measurement is a crucial prerequisite for ensuring stable and accurate flow control. Currently, there are many types of flow meters, among which gear flow meters (including circular gear flow meters and elliptical gear flow meters) are widely used in petroleum, chemical, food, and pharmaceutical fields due to their simple principle, compact structure, and ability to measure fluids of various viscosities. Traditional gear flow meters are mostly mechanical, easily transmitting gear rotation information via a transmission chain and converting it into corresponding displacement data.

[0003] To meet the needs of automated production, various types of electronic gear flow meters have been invented. Currently, the most popular type on the market is the Hall effect-based electronic gear flow meter. Its working principle is as follows: each time the gear pair rotates a tooth, the magnetic flux between the housing and the tooth changes, causing a change in output voltage. Through a conditioning circuit, the flow meter generates a voltage or current pulse each time it rotates a tooth. This type of electronic flow meter can easily achieve real-time digital display of flow rate. However, because the number of teeth on the gear is relatively small, the number of pulses output per rotation is also small, which means that the measurement resolution is low and the accuracy is poor. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the existing technology and provide an electronic gear flow meter based on a rotary encoder. This rotary encoder-based electronic gear flow meter has low resolution and poor accuracy.

[0005] Meanwhile, another objective of the present invention is to provide a measurement method for an electronic gear flow meter based on a rotary encoder.

[0006] The objective of this invention is achieved through the following technical solution: This electronic gear flow meter based on a rotary encoder includes a mechanical gear flow meter, a rotary encoder, a decoder, and a subdivision algorithm module. The output shaft of the mechanical gear flow meter is connected to the code disk of the rotary encoder, and both the subdivision algorithm module and the decoder are connected to the rotary encoder.

[0007] Preferably, the rotary encoder includes a code disk, an encoder shaft, a light source, a photoelectric converter, and a conditioning circuit. The code disk is mounted on the encoder shaft, and the light source and photoelectric converter are respectively mounted on both sides of the code disk, with the light source and photoelectric converter facing each other. The photoelectric converter is connected to the conditioning circuit, and the subdivision algorithm module and the decoder are both connected to the conditioning circuit.

[0008] Preferably, the adjustment circuit and the subdivision algorithm module are integrated into a processing circuit. The processing circuit includes a pulse counting module and five voltage comparators, namely a first voltage comparator, a second voltage comparator, a third voltage comparator, a fourth voltage comparator, and a fifth voltage comparator. The input terminals of the first voltage comparator, the second voltage comparator, the third voltage comparator, the fourth voltage comparator, and the fifth voltage comparator are all connected to the photoelectric converter. The first voltage comparator is connected to both the pulse counting module and the decoder, and the output terminal of the third voltage comparator is connected to the decoder. The second voltage comparator, the fourth voltage comparator, and the fifth voltage comparator are all connected to the pulse counting module.

[0009] Preferably, the pulse counting module includes a first AND gate, a calculator, and a latch connected in sequence. The outputs of the first voltage comparator, the fourth voltage comparator, and the fifth voltage comparator are all connected to the first AND gate, and the output of the second voltage comparator is connected to the calculator.

[0010] Preferably, the mechanical gear flow meter includes a first gear, a second gear, an output shaft, a rotating shaft, and a housing. The first gear and the second gear are respectively installed in the inner and outer housings via the output shaft and the rotating shaft. The output shaft is connected to the encoder shaft via a coupling. After the first gear and the second gear mesh, the inner cavity of the housing is divided to form an upstream cavity and a downstream cavity with a pressure difference.

[0011] The measurement method of the electronic gear flow meter based on the rotary encoder, using the aforementioned electronic gear flow meter based on the rotary encoder, includes the following steps:

[0012] S1. The mechanical gear flow meter drives the rotary encoder. The rotary encoder outputs three-phase sinusoidal or square wave signals A, B and Z through the conditioning circuit. The phase difference between the A and B phase signals is 90°.

[0013] S2. The decoder decodes the output A, B and Z phase signals to determine the number of rotations of the output shaft of the mechanical gear flow meter and the zero point position, and at the same time determines the cumulative rotation angle position and rotation direction of the output shaft of the mechanical gear flow meter.

[0014] S3, the segmentation algorithm module processes the decoding information of the decoder to calculate the traffic.

[0015] Preferably, the specific process in step S2 includes the following steps:

[0016] S21. Number of revolutions and zero position determination: On the one hand, the Z-phase signal provides the absolute zero angle position; on the other hand, pulse counting is performed on the Z-phase signal to determine the number of revolutions n of the flowmeter output shaft.

[0017] S22. Angular displacement calculation: Perform pulse readings on the A-phase signal to determine the rotation angle θ of the output shaft.

[0018] This is equation (1);

[0019] Where M is the number of slits on the code disk, and m is the pulse count value of the A-phase signal;

[0020] Based on equation (1), the cumulative rotational angular displacement θ of the output shaft of the mechanical gear flow meter is obtained. total :

[0021] This is equation (2);

[0022] S23. Rotation direction determination: Perform quadrature decoding on phase A and phase B signals to determine the phases of phase A and phase B signals:

[0023] If the A-phase signal leads the B-phase signal, the output shaft is determined to be rotating in the forward direction, and the rotation angle position is recorded as +θ.

[0024] If the A-phase signal lags behind the B-phase signal, it is determined that the encoder (or flowmeter output shaft) is in reverse, and the rotational angular displacement is recorded as -θ.

[0025] Preferably, step S3 includes the following steps:

[0026] S31. Let the A-phase signal be a sinusoidal signal, then U A =sinα, this is equation (3), where U A α is the amplitude of the A-phase signal of the rotary encoder, and α is the phase angle;

[0027] S32. Let the subdivision factor be L. Then, within one sinusoidal signal period, the phase angles corresponding to the L subdivision positions are as follows:

[0028] This is Equation 4), where the value of i is 0, 1, 2, ..., L-1;

[0029] The voltage amplitudes corresponding to the L subdivision positions are as follows:

[0030] U i =sinα i This is equation (5), where the value of i is 0, 1, 2, ..., L-1;

[0031] S33, after each U i The logic circuit outputs a subdivision pulse, which is counted and denoted as l. After subdivision, the rotational angular displacement of the flowmeter output shaft is equal to: This is equation (6); and the corner resolution is:

[0032] S34. Calculate the final flow rate Q and flow resolution ΔQ using the rotational angular displacement and angular resolution from step S33:

[0033]

[0034]

[0035] The present invention has the following advantages over the prior art:

[0036] 1. Compared to electronic gear flow meters based on the Hall effect (where the flow resolution is determined by the number of teeth Z, equal to...) The electronic gear flow meter based on a rotary encoder proposed in this invention has a flow resolution determined by the number of encoder slits and the subdivision factor, which is equal to... Simultaneously, the detection results of the mechanical gear flow meter are converted into photoelectric signals, and the signals obtained from the photoelectric conversion are processed, thereby significantly improving the measurement accuracy of the gear flow meter.

[0037] 2. This invention utilizes the phase difference between the A and B phase signals output by the rotary encoder to determine the flow direction through the gear flow meter.

[0038] 3. This invention converts flow information into angular displacement information of a rotary encoder. Currently, almost all CNC systems are equipped with encoder decoders. Therefore, flow information can be conveniently fed back directly to the CNC system, which will greatly facilitate the development of flow control systems based on CNC systems and servo motors. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the electronic gear flow meter based on a rotary encoder according to the present invention.

[0040] Figure 2 This is a schematic diagram of the rotary encoder of the present invention.

[0041] Figure 3 This is a schematic diagram of the A, B, and Z three-phase signals of the present invention.

[0042] Figure 4 This is a schematic diagram (I) of the subdivision algorithm module of the present invention.

[0043] Figure 5This is the schematic diagram II of the subdivision algorithm module of the present invention.

[0044] Figure 6 This is the circuit diagram of the present invention.

[0045] Among them, 1 is a mechanical gear flow meter, 2 is a rotary encoder, 3 is a decoder, 4 is a subdivision algorithm module, 5 is a code disk, 6 is an encoding shaft, 7 is a light source, 8 is a photoelectric converter, 9 is a conditioning circuit, 10 is a first voltage comparator, 11 is a second voltage comparator, 12 is a third voltage comparator, 13 is a fourth voltage comparator, 14 is a fifth voltage comparator, 15 is a pulse counting module, 16 is a first AND gate, 17 is a calculator, 18 is a latch, 19 is a D flip-flop, 20 is a second AND gate, 21 is an oscilloscope, 22 is a first gear, 23 is a second gear, 24 is an output shaft, 25 is a rotating shaft, 26 is a housing, and 27 is a coupling. Detailed Implementation

[0046] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0047] like Figure 1 , Figure 2 and Figure 6 The electronic gear flow meter based on a rotary encoder shown includes a mechanical gear flow meter, a rotary encoder, a decoder, and a subdivision algorithm module. The output shaft of the mechanical gear flow meter is connected to the code disk of the rotary encoder, and both the subdivision algorithm module and the decoder are connected to the rotary encoder.

[0048] Specifically, the rotary encoder outputs three-phase sinusoidal signals A, B, and Z, where the phase difference between phases A and B is 90°. ° Each rotation of the master encoder generates one pulse in the Z phase, called a "rotation pulse". The A, B, and Z phase signals are as follows: Figure 3 As shown, the decoder and subdivision algorithm modules process the A, B, and Z phase signals respectively, thereby improving the detection accuracy and precision of the electronic gear flow meter and providing a reliable guarantee for the CNC system.

[0049] like Figure 2 As shown, the rotary encoder includes a code disk, an encoder shaft, a light source, a photoelectric converter, and a conditioning circuit. The code disk is mounted on the encoder shaft, and the light source and photoelectric converter are respectively mounted on both sides of the code disk, facing each other. The photoelectric converter is connected to the conditioning circuit, and the subdivision algorithm module and the decoder are both connected to the conditioning circuit. Specifically, the encoder shaft is connected to the output shaft of the mechanical gear flow meter via a coupling, so that the code disk mounted on the encoder shaft can rotate synchronously with the gears in the mechanical gear flow meter, thereby ensuring the accuracy of the detection.

[0050] The adjustment circuit and subdivision algorithm module are integrated into a processing circuit. The processing circuit includes a pulse counting module and five voltage comparators, designated as a first, second, third, fourth, and fifth voltage comparator. The input terminals of the first, second, third, fourth, and fifth voltage comparators are all connected to the photoelectric converter. The first voltage comparator is connected to both the pulse counting module and the decoder, and the output terminal of the third voltage comparator is connected to the decoder. The second, fourth, and fifth voltage comparators are all connected to the pulse counting module, as shown in the specific connections below. Figure 6 As shown. The adjustment circuit and subdivision algorithm module optimize the circuit design and improve processing efficiency. The integrated processing circuit implements the conditioning and subdivision algorithm functions through a voltage comparator, using the A, B, and Z three-phase signals as the positive input terminal V of the voltage comparator. I Using a subdivided reference voltage as the inverting phase input V P By comparing the two, the shaped output can be identified as high or low level signals by counters, D flip-flops, etc.; the first voltage comparator, the fourth voltage comparator, and the fifth voltage comparator can achieve 6x frequency subdivision by subdividing the signal period of the sinusoidal signal of each slit of the code disk by a factor of 6. The specific principle is as follows: Figure 4 and Figure 5 As shown:

[0051] Step 1: U i Given that U1 = 0, U2 = sinpi / 3, U3 = sin2pi / 3, U4 = sinpi, U5 = sin4pi / 3, and U6 = sin5pi / 3, we can see that U2 = U3, U1 = U4, and U5 = U6.

[0052] Step 2: In channel C1, a high level is applied when the voltage is greater than U1, and a low level is applied otherwise. The same comparison is performed sequentially. Therefore, in channels C2 to C6, a high level is applied when the voltage is greater than the comparison voltage set for each channel, and a low level is applied otherwise. The results are as follows: Figure 4 As shown.

[0053] Step 3: Identify the rising and falling edges in channels C1 to C6, assigning them a high level value, and the others a low level value. The identification results are D1 to D6. Then, perform an OR gate operation on D1 to D6, and then in all U... i A high-level pulse will appear at each location, such as Figure 5 As shown.

[0054] Higher frequency multiplication can be selected as needed; when combined with a gear flow meter with a displacement q of 2 ml / r, the displacement resolution can reach 6.7 × 10⁻⁶. -5 ml / pulse, with a flow resolution of up to 6.7 × 10⁻⁶. -5 Compared to a Hall effect-based electronic gear flow meter with 10 teeth and a displacement of 2 ml / r, which has a displacement resolution of only 0.2 ml / pulse, the flow meter's displacement and flow resolution are both increased by 2985 times after incorporating a rotary encoder.

[0055] The pulse counting module includes a first AND gate, a calculator, and a latch connected in sequence. The outputs of the first, fourth, and fifth voltage comparators are all connected to the first AND gate, and the output of the second voltage comparator is connected to the calculator. The input of the first AND gate is connected to the subdivided A-phase pulse signal from the outputs of the first, fourth, and fifth voltage comparators. The output signal of the first AND gate is sent to the U / D interface of the counter. The output of comparator 2 is the conditioned Z-phase pulse signal, which is connected to the RESET interface of the counter for clearing the pulse count and then transmitting it to the latch to prevent data errors.

[0056] The decoder consists of a D flip-flop, a second AND gate, and an oscilloscope connected in sequence. The D interface of the D flip-flop is connected to the output of the third voltage comparator, and the CLK interface of the D flip-flop is connected to the output of the first voltage comparator, thereby realizing the phase difference between the A and B phase signals.

[0057] The mechanical gear flow meter includes a first gear, a second gear, an output shaft, a rotating shaft, and a housing. The first gear and the second gear are respectively mounted inside the outer and inner housings via the output shaft and the rotating shaft. The output shaft is connected to an encoder shaft via a coupling. After the first gear and the second gear mesh, the inner cavity of the housing is divided to form an upstream cavity and a downstream cavity with a pressure difference. This structure is simple, has good stability, and further ensures the accuracy of the detection.

[0058] The measurement method of the electronic gear flow meter based on the rotary encoder, using the aforementioned electronic gear flow meter based on the rotary encoder, includes the following steps:

[0059] S1. The mechanical gear flow meter drives the rotary encoder. The rotary encoder outputs three-phase sinusoidal or square wave signals A, B and Z through the conditioning circuit. The phase difference between the A and B phase signals is 90°.

[0060] S2. The decoder decodes the output A, B and Z phase signals to determine the number of rotations of the output shaft of the mechanical gear flow meter and the zero point position, and at the same time determines the cumulative rotation angle position and rotation direction of the output shaft of the mechanical gear flow meter.

[0061] The specific process in step S2 includes the following steps:

[0062] S21. Number of revolutions and zero position determination: On the one hand, the Z-phase signal provides the absolute zero angle position; on the other hand, pulse counting is performed on the Z-phase signal to determine the number of revolutions n of the flowmeter output shaft.

[0063] S22. Angular displacement calculation: Perform pulse readings on the A-phase signal to determine the rotation angle θ of the output shaft.

[0064] This is equation (1);

[0065] Where M is the number of slits on the code disk, and m is the pulse count value of the A-phase signal;

[0066] Based on equation (1), the cumulative rotational angular displacement θ of the output shaft of the mechanical gear flow meter is obtained. total :

[0067] This is equation (2);

[0068] S23. Rotation direction determination: Perform quadrature decoding on phase A and phase B signals to determine the phases of phase A and phase B signals:

[0069] If the A-phase signal leads the B-phase signal, the output shaft is determined to be rotating in the forward direction, and the rotation angle position is recorded as +θ.

[0070] If the A-phase signal lags behind the B-phase signal, it is determined that the encoder (or flowmeter output shaft) is in reverse, and the rotational angular displacement is recorded as -θ.

[0071] S3, the segmentation algorithm module processes the decoding information of the decoder to calculate the traffic.

[0072] Step S3 includes the following steps:

[0073] S31. Let the A-phase signal be a sinusoidal signal, then U A =sinα, this is equation (3), where U A α is the amplitude of the A-phase signal of the rotary encoder, and α is the phase angle;

[0074] S32. Let the subdivision factor be L. Then, within one sinusoidal signal period, the phase angles corresponding to the L subdivision positions are as follows:

[0075] This is Equation 4), where the value of i is 0, 1, 2, ..., L-1;

[0076] The voltage amplitudes corresponding to the L subdivision positions are as follows:

[0077] U i =sinα iThis is equation (5), where the value of i is 0, 1, 2, ..., L-1;

[0078] S33, after each U i The logic circuit outputs a subdivision pulse, which is counted and denoted as l. After subdivision, the rotational angular displacement of the flowmeter output shaft is equal to: This is equation (6); and the corner resolution is:

[0079] S34. Calculate the final flow rate Q and flow resolution ΔQ using the rotational angular displacement and angular resolution from step S33:

[0080]

[0081]

[0082] The above-described specific embodiments are preferred embodiments of the present invention and are not intended to limit the present invention. Any other changes or equivalent substitutions made without departing from the technical solution of the present invention are included within the protection scope of the present invention.

Claims

1. A measurement method for an electronic gear flow meter based on a rotary encoder, characterized in that, An electronic gear flow meter based on a rotary encoder is adopted. This electronic gear flow meter based on a rotary encoder includes a mechanical gear flow meter, a rotary encoder, a decoder, and a subdivision algorithm module. The output shaft of the mechanical gear flow meter is connected to the code disk of the rotary encoder, and the subdivision algorithm module and the decoder are both connected to the rotary encoder. The rotary encoder includes a code disk, an encoder shaft, a light source, a photoelectric converter, and a conditioning circuit. The code disk is mounted on the encoder shaft, and the light source and photoelectric converter are respectively mounted on both sides of the code disk, with the light source and photoelectric converter facing each other. The photoelectric converter is connected to the conditioning circuit, and the subdivision algorithm module and the decoder are both connected to the conditioning circuit. The conditioning circuit and the subdivision algorithm module are integrated into a processing circuit, which includes a pulse counting module and five voltage comparators. The five voltage comparators are designated as a first voltage comparator, a second voltage comparator, a third voltage comparator, a fourth voltage comparator, and a fifth voltage comparator. The input terminals of the first, second, third, fourth, and fifth voltage comparators are all connected to the photoelectric converter. The first voltage comparator is simultaneously connected to both the pulse counting module and the decoder, and the output terminal of the third voltage comparator is connected to the decoder. The second, fourth, and fifth voltage comparators are all connected to the pulse counting module. Includes the following steps: S1. The mechanical gear flow meter drives the rotary encoder. The rotary encoder outputs three-phase sinusoidal or square wave signals A, B and Z through the conditioning circuit. The phase difference between the A and B phase signals is 90°. S2. The decoder decodes the output A, B and Z phase signals to determine the number of rotations of the output shaft of the mechanical gear flow meter and the zero point position, and at the same time determines the cumulative rotation angle position and rotation direction of the output shaft of the mechanical gear flow meter. The specific process in step S2 includes the following steps: S21. Rotation Count and Zero Point Position Determination: On one hand, the Z-phase signal provides the absolute zero-angle position; on the other hand, pulse counting is performed on the Z-phase signal to determine the total number of rotations of the flowmeter output shaft. ; S22. Angular displacement calculation: Perform pulse readings on the A-phase signal to determine the rotation angle of the output shaft. : This is equation (1); Where M is the number of slits on the code disk, and m is the pulse count value of the A-phase signal; Based on equation (1), the cumulative rotational angular displacement of the output shaft of the mechanical gear flowmeter is obtained. : This is equation (2); S23. Rotation direction determination: Perform quadrature decoding on phase A and phase B signals to determine the phases of phase A and phase B signals: If phase A signal leads phase B signal, the output shaft is determined to be rotating clockwise, and the rotation angle position is recorded as follows: ; If the A-phase signal lags behind the B-phase signal, the encoder is determined to be in reverse, and the rotational angular displacement is denoted as... ; S3, the segmentation algorithm module processes the decoding information from the decoder to calculate the traffic.

2. The measurement method of the electronic gear flow meter based on a rotary encoder according to claim 1, characterized in that, Step S3 includes the following steps: S31. Let the A-phase signal be a sinusoidal signal, then This is equation (3), where The amplitude of the A-phase signal of the rotary encoder. Phase angle; S32. Let the subdivision factor be L, then within one sinusoidal signal period, The phase angles corresponding to each subdivision position are as follows: This is equation (4), where, The value is ; The voltage amplitudes corresponding to each subdivision position are as follows: This is equation (5), where, The value is ; S33, after each The logic circuit outputs a subdivision pulse, and the subdivision pulses are counted, with the value recorded as follows: After subdivision, the rotational angular displacement of the flowmeter output shaft is equal to: This is equation (6); and the angular resolution is: ; S34. Calculate the final flow rate using the rotational angular displacement and angular resolution from step S33. and traffic resolution : ， 。 3. The measurement method of the electronic gear flow meter based on a rotary encoder according to claim 1, characterized in that: The pulse counting module includes a first AND gate, a calculator, and a latch connected in sequence. The outputs of the first voltage comparator, the fourth voltage comparator, and the fifth voltage comparator are all connected to the first AND gate, and the output of the second voltage comparator is connected to the calculator.

4. The measurement method of the electronic gear flow meter based on a rotary encoder according to claim 1, characterized in that: The mechanical gear flow meter includes a first gear, a second gear, an output shaft, a rotating shaft, and a housing. The first gear and the second gear are respectively installed in the inner and outer housings via the output shaft and the rotating shaft. The output shaft is connected to the encoder shaft via a coupling. After the first gear and the second gear mesh, the inner cavity of the housing is divided to form an upstream cavity and a downstream cavity with a pressure difference.

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